Task force to suggest steps to prevent flooding in Dane County

Joman Schachter makes his way down the Yahara River in an inner tube on Aug. 23 at Tenney Park. Dane County officials are considering taking various steps to prevent flooding from causing so much damage again. (Amber Arnold/Wisconsin State Journal via AP)

MADISON, Wis. (AP) — A task force is planning to recommend ways Dane Count can prevent the sort of flooding that occurred there after torrential rains caused lakes to spill over last summer, prompting evacuations.

A study released this month identified various ways for Dane County to lower flood levels in the Yahara chain of lakes, which include lakes Mendota and Monona. The task force assembled by the county’s Board of Supervisors is reviewing the report and plans to present recommendations to county officials by April 1, Wisconsin Public Radio reported.

Dane County budgeted more than $18 million this year for flood mitigation. The decision came after then-Gov. Scott Walker declared a state of emergency in the county in August, when flooding drenched streets and damaged homes.

The new report identified two ways of managing lakes: adaptation and mitigation. Adaptation would make the area less vulnerable to flooding without eliminating fundamental deficiencies, while mitigation would deal with the underlying issues.

“Fundamentally, what the report says is that in order to reduce future flooding, we need to improve flow in the system,” said Sharon Corrigan, chairman of the county board. “Because our lake system is very flat, water that comes into the system, stays in the system, even if we have everything opened up wide.”

Two mitigation plans, dredging and pumping, were identified in the report as being the most effective. Dredging would remove excess sediment and material from the Yahara River. Pumping would reroute water from the lake chain to another body of water, such as Badfish Creek near Cooksville. Using the two methods together could lower flood levels by 7 to 21 inches, according to the report.

That option would have its own drawbacks. Dredging, for instance, could inflict harm on historical artifacts.

The adaptation methods include lowering the level of Lake Mendota by a foot, and removing all dams from the lakes chain.

The task force will be seeking public comments before making its recommendations.